He then tells the dispatcher that he doesn't know what happened, but said, "I saw a lot of, a lot of, a lot of screaming. So I (inaudible) go inside, I saw the lady on the floor."

Police said Gonzalez's co-worker, Jorge Lachazo, 21, of Hialeah, beat Smith Udell with a mallet and doused her with a chemical he found in the house. He claimed it spontaneously combusted, authorities said.

Police said Lachazo fled the scene in the delivery truck while his co-worker was on the phone with the dispatcher.

A police officer responding to the call stopped the white delivery truck and noticed the hairs on Lachazo's legs were burned and had ash on them, police said.

Smith Udell, a former longtime librarian at Florida Atlantic University, was taken to Delray Medical Center, where she later died.